Different embodiments of garden swings or seesaws made of plastic material are already known, in which, however and invariably, each shoulder is en bloc, i.e., is molded in a single piece of large dimensions. The shoulders produced in this manner, given their space occupied and not being able to be disassembled, place remarkable problems in the way of packing and of shipping and, when assembled, they require particular measures and means for the stability of the structure of the swing.